Power actuator for doors



E. J. NIEDHAMMER, m" ETAL ,7575% POWER ACTUATOR FOR DOORS 2 Sheets-Sheet 1 Filed Aug. l, 1952 Inventors:

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Edwin J. NiedhammenJn mm v w Q. with Jr;

E U 0 W w A W w W Aug 7? 1956 E1. NIEDHAMMEIR, .m, E'rm. 2,3575% POWER ACTUATOR FOR DOORS Filed Aug. 1, 19:52 2 Sheets-Sheet 2 In venkors:

Edwin J. Nic-mihammenmz POWER ACTUATOR FOR DOORS Edwin John Niedhammer, Jr., and William C. Smith, Jr.,

Schenectady, N. Y., assignors to General Electric Company, a corporation of New York Application August 1, 1952, Serial No. 302,266

1 Claim. (Cl. 74-520) This invention relates to motor-driven actuators, par: ticularly to a mechanical actuator for opening and closing a heavily loaded swinging door. 1

An object of the present invention is to provide an improved floating motor-driven door linkage mechanism actuator which occupies a very small amount of space, and which floats the driving motor, for all positions of the door, closely adjacent the door and wall portion to which the door is hinged, and which changes the floating position of the driving motor only very little as the door swings through its normal range of movement.

Another object is to provide a door actuator of the type described wherein the floating driving motor is selfcontained and self-supported, so that the entire linkage mechanism requires only one pivoted point of attachment to the door and one pivoted point of attachment to the wall.

A further object is to provide a power actuator which is positive in its operation and self-locking, so the door will not move under the loads applied to it in the event of a power failure.

A still further object is to provide an improved door actuating mechanism which can be readily fabricated as a simple integral unit readily applied to any swinging door.

Other objects. and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which Fig. l is a top view of a single door actuator in accordance with the invention, with a portion of the main frame plate broken away to show more clearly the actuating linkage, Fig. 2 is an end view, in elevation, of the actuator of Fig. 1, Fig. 3 is a diagrammatic representation illustrating the method of application of the actuator to a swinging door, showing both the open and closed positions, and Fig. 4 is a detail view, taken on the plane 4-4 in Fig. 1.

Generally stated, the invention is practiced by providing a lazy-tongs" parallelogram type of linkage having diagonally opposite pivots adapted to be connected to the door and wall, respectively, while a floating motor-driven lead-screw having oppositely threaded end portions spans the linkage between the other diagonally opposite corners. A traveling nut carried on each oppositely threaded end portion of the lead-screw supports the pivots for the respective pairs of adjacent links.

Referring now more particularly to Fig. l, the actuator comprises a rectangular floating frame plate 1, on one side of which is mounted a suitable reversible electric motor 2, and which on its other side carries a longitudinally disposed lead-screw 3 supported in suitable bearings 4, 5, 6 and 7. These bearings. may be conventional pillow blocks secured to the frame plate by bolts a. At least one of these pillow blocks also serves as a thrust bearing, and to this end the lead-screw is provided with thrust collars 3a, 3b, engaging the respective inner end thrust faces of the pillow blocks 4 and 5. The lead screw screw 3 has oppositely threaded end portions and an intermediate portion of lead-screw 3 is supported in the pillow blocks 6, 7, between which is disposed a large driven J nited States Patent 0 "ice gear 8 suitably fastened to drive screw 3 and projecting through an opening 1a in a frame plate 1 to mesh with a driving pinion 2a carried on the shaft of motor 2 which floats along with the frame plate 1.

The lazy-tongs linkage defines a parallelogram the sides of which are formed by four similar link members 9, 10, 11, 12. Each link may be conveniently formed of a mid-portion of tubular section shown at 10a, to one end of which is welded a forked fitting 1% through which is disposed the transverse pivot pin 100. At the other end of tubular portion 10a there is welded a somewhat similar forked end member 10d. The adjacent forked ends 9a, 100. are secured by a common pivot pin 13 to a universal joint spider 14, the other axis of which is defined by a pair of end pivot portions 14a, 14b journalled in the spaced legs of a U-shaped attachment fitting 15, which is adapted to be secured to the wall from which the door is hung.

Similarly, the adjacent ends of links 11, 12 are provided with forked end portions 11d, 12d secured by a common pivot pin 16 to a universal joint spider member 17 having end portions 17a, 17b journalled in an attach mentbracket 18 adapted to be secured to the door memher.

The respective ends of lead-screw 3 carry traveling nut members 19, 20. As will be understood from a comparison of Figs. 1 and 2, the nut 20 is provided with a pair of oppositely extending ears 20a, 2%, which are connected by the pivots 10c, to the forked end fittings 10b, 12b of links 10 and 12, respectively. The nut 19 is, of course, similarly connected by pivots 9c, 11c to the forked end fittings 9/), 11b of links 9, 11.

It will be apparent that rotation of the reversible motor 2 will cause nuts 19, 20 to move along lead-screw 3 so as to change the shape of the parallelogram linkage, 9, 10, 11, 12. When the nuts 19, 20 move toward each other, the attachment fittings 15, 18 move away from each other, and vice versa. Travel of the nuts is limited in the following manner. Nut 20 carries a lug 20c which extends upwardly through an elongated slot (not shown) in plate 1 and is adapted to engage, at one extreme position, the actuating member 21 of a suitable limit switch 22. At the other extreme position, lug 20c engages the actuating member 23 of a limit switch 24. These limit switches may be conveniently secured to the top side of the main frame plate 1, as shown in Fig. 2. The plan location of these switches is indicated in dotted lines in Fig. 1. They are, of course, connected in circuit with the motor 2 so that the motor stops whenever the respective limiting conditions are reached. The details of the electrical power supply and control circuits. for the motor 2 are not material to an understanding of the present invention and are therefore not disclosed herein.

The parallelogram linkage is stabilized against the torque reaction of the floating motor 2 in the following manner. Each link has secured thereto a projecting ear member, as shown at 25 in Fig. 1, to which is pivoted a roller guide, which may conveniently take the form of a caster wheel 26, as will be seen more clearly in Fig. 4. The other links are provided with similar caster wheels, as indicated at 27, 2S, and 29 in Fig. 1. These four caster wheels bear against the bottom surface of the main frame plate 1, as also shown in Fig. 4. These casters are, of course, so located on the links that each caster will ride on the frame plate 1 for all positions of the linkage. The reaction between these casters and the frame plate absorbs the torque reaction of the motor 2, and insures that the links will remain in a plane parallel to the frame plate regardless of any bending or twisting couples applied to the linkage by the loads thereon.

Fig. 3 illustrates one way in which the actuator may be applied to a swinging door. The door member 30 is supported from the adjacent wall 31 by hinge 32. The

attachment fitting 18 of the actuator is secured to the door a short distance from the hinge, and the other fitting 15 is secured to a suitable bracket 33 supported from the wall. To insure proper operation of the actuator, it is essential that the universal joint spider members 14 and .17 carried by the mounting brackets 15 and 18 have parallel axes spaced apart for free floating movement of the motor mounting frame plate 1 and the operating linkage in parallel relation with each other and with the axes of the spider members in the space therebetween as the door swings open or shut. At the righthand side of Fig. 3 the cooperating door 34, supported from wall 35 by a hinge 36 is shown in closed position.

It will be observed thatthe actuator is supported closely adjacent the respective walls 31, 35, projecting only very slightly into the door opening defined between walls 31, 35 so as to offer very little obstruction to the door area. Equally important is the fact that the actuating devices move only a comparatively short distance as the door goes from closed to open position, so that for no position of the door does the actuating mechanism seriously obstruct the doorway.

The actuator is a self-contained unit readily applicable to almost any swinging door, requiring only one connection to the door and one to the adjacent wall. Because of the self-locking nature of the lead-screw drive, the door will be positively supported in the event the power should fail.

It will be seen that the invention provides a simple, rugged actuator for power-operated doors which occupies very little space and can be conveniently fabricated as a unit which is easily installed since it requires only one connection to the door and one to the adjacent wall.

It will be obvious to those skilled in the art that many minor alterations and substitutions of mechanical equivalents may be made; and it is of course desired to cover by the appended claims all such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

A mechanical power actuator comprising a pair of relatively movable attachment brackets provided with separate universal joint spider members having spaced apart parallel axes, an elongated floating frame plate having a reversible motor mounted thereon, a lead-screw disposed longitudinally and parallel to the frame plate and having oppositely threaded end portions, bearing means supporting the lead-screw on the frame plate, gear means connecting the motor to rotate the leadscrew, a first traveling nut member carried on one end portion of the lead-screw, a second traveling nut member carried on the other end portion of the lead-screw, and a parallelogram linkage composed of two pairs of similar links, one pair having end portions pivotally connected to the first traveling nut and the other pair having end portions pivoted to the second traveling nut, means pivotally connecting the adjacent ends of one link of each of said pairs of links to one of the spider members, means pivotally connecting to the adjacent ends of the other pair of links to the other spider members, each link having secured thereto a roller member engaging the adjacent surface of the frame plate for all positions 'of the links to maintain the parallelogram linkage parallel to the floating plate and the plate parallel to the axes of the spider members to absorb the torque reaction of the motor.

References Cited in the file of this patent UNITED STATES PATENTS 161,751 Butterworth 'Apr. 6, 1875 391,141 Golightly Oct. 16, 1888 1,365,252 Langill Jan. 11, 1921 2,218,733 Watts Oct. 22, 1940 2,344,594 Bryant Mar. 21, 1944 2,661,327 Hulsart Dec. '8, 1953 FOREIGN PATENTS 146,315 Austria June 25, 1936 243,712 Italy Apr. 15, 1926 

